Celebrating the past six years in STAR
By Jamie Dunlop
Last year, while the candidates for the U.S. Presidency were
stumping for their election, the STAR experiment was holding its
own election for the position of Spokesperson. Like the U.S.
President, the Spokesperson is limited to two terms in office,
which, in STAR’s case, spans 6 years. The latest term ended this
past February. This past Monday, a symposium at BNL was held to
celebrate the leadership of Tim Hallman, STAR Spokesperson for
the past 6 years, to chronicle the experiment’s success and look
forward to its future.
The years from 2002-2008 were very productive for STAR. At the beginning of this time, results from the first run at RHIC had begun to come out, which were exciting and new, but still not well understood. Jet quenching and large levels of elliptic flow had been observed, but the observations were of limited precision and the mechanisms that caused the observations not clear. A decisive test of the mechanism underlying jet quenching was made in 2003 with the d+Au run, which clearly showed that jet quenching was caused by energy loss in the medium produced at RHIC, a discovery that made the front page of Physical Review Letters with papers from all four RHIC experiments. This and other observations were collected and digested in the RHIC Whitepapers in 2005, which summarized what the experiments had learned in the first three years of RHIC running. These whitepapers have had a major impact on science: the “Perfect Liquid” discovery, based on these whitepapers, was named the number one physics story by the AIP in 2005, and these papers continue to make top citation lists.
A number of other extremely important results have followed, made possible by the 6 RHIC runs of various species that occurred during this time, combined with upgrades to the detectors. There is no space in this article to go through all the exciting results that have been produced during this time: they are covered in the 72 articles published in the refereed literature, a record unmatched in Nuclear Physics, and to some level in the talks at the symposium. STAR has also played a large role in training the next generation of scientists, graduating approximately 100 students in the past 6 years. RHIC is entering a new phase, in which major upgrades to the detectors, launched in the latter part of the past 6 years, and improvements in the luminosity delivered by the accelerator, will allow us to characterize the properties of the new state of matter created at RHIC with high precision. We have found a number of major surprises along the way, and the results are hinting there may be more big surprises to come.
References
For STAR’s full publication list, see http://www.star.bnl.gov/central/publications
The Relativistic Heavy Ion Collider at Brookhaven National
Laboratory is a world-class scientific research facility primarily
funded by the U.S. Department of Energy Office of Science. Hundreds
of physicists from around the world use RHIC to study what the
universe may have looked like in the first few moments after its
creation. What physicists learn from these collisions may help us
understand more about why the physical world works the way it does,
from the smallest subatomic particles, to the largest stars.